GCN Circular 15212

V. D'Elia (ASDC), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC),
D. Malesani (DARK/NBI), C. B. Markwardt (NASA/GSFC),
K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of
the Swift Team:

At 08:34:57 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 130912A (trigger=570465).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 47.615, +13.974 which is 
   RA(J2000) = 03h 10m 28s
   Dec(J2000) = +13d 58' 28"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a short spike
with substructure with a duration of about 0.5 sec.  The peak count rate
was ~11000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 08:36:31.7 UT, 93.9 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 47.59060, 13.99546 which is equivalent
to:
   RA(J2000)  = 03h 10m 21.74s
   Dec(J2000) = +13d 59' 43.7"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 115 arcseconds from the BAT onboard position, within the
BAT error circle. This position may be improved as more data are
received; the latest position is available at
http://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (1.24 x
10^21 cm^-2, Kalberla et al. 2005), with an excess column of 2.1
(+1.66/-1.48) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 98 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers none of
the XRT error circle. The 8'x8' region for the list of sources generated
on-board covers 100% of the XRT error circle. The list of sources is typically
complete to about 18 mag. No correction has been made for the expected
extinction corresponding to E(B-V) of 0.28. 

Burst Advocate for this burst is V. D'Elia (delia AT asdc.asi.it). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)